It's time to heatproof our cities

23 Comments

'Heatwave gravestone' by Chris Johnston features a gravestone in the shape of a non-heatwave resistant mansion, with the inscription 'John Doe, 1960-2020, Heat stroke'A few weeks ago, as a cool change swept away Melbourne's mid-January heatwave, my partner and I went for a walk around our block. The air temperature had plummeted about ten degrees in 30 minutes, but as we passed a new two-storey home with no surrounding vegetation and a mound of gravel for a front lawn, I felt a surge of residual warmth. The house's dark-grey exterior seemed to shimmer with stored-up heat.

Hurrying on, I wondered how this house — and so many others like it — would cope with future heatwaves.

Climate change has loaded the dice towards hotter days and more frequent heat spells. Australia's average temperature has increased 0.9 degrees since 1910, while the number of record hot days has doubled since 1960. 'Although Australia has always had heatwaves, hot days and bushfires, climate change has increased the risk of more intense heatwaves and extreme hot days, as well as exacerbated bushfire conditions,' explained the Climate Commission's 2013 report 'Off the Charts: Extreme Australian summer heat'.

Heatwaves don't create the same dramatic news footage as bushfires, floods and cyclones, but they kill more people. From 1844 to 2010, heatwaves were responsible for at least 5332 deaths in Australia, and since 1900 they've killed more Australians than all other natural hazards combined. The January 2009 heatwave in Victoria, when Melbourne sweltered through three consecutive days of temperatures above 43 degrees, resulted in 374 deaths. In comparison, the Black Saturday fires took 173 lives.

While peak temperatures fell short of the 2009 heatwave, the severely hot weather across south-eastern Australia from 13 to 18 January this year lasted longer in many places. Adelaide had a record five consecutive days of 42 degrees and above, and Canberra had a record four consecutive days of 39 degrees. Sydney was spared the worst of the heatwave this time around, but last January the city registered its hottest day on record.

Meanwhile, Victoria had a record-breaking average maximum temperature of more than 41 degrees across four successive days, resulting in 139 'excess' deaths in the period up to 23 January.

The elderly are more vulnerable to extreme heat, and Australia's ageing population means we can expect the death toll to rise in the future. But the biggest impact will come from climate change. A November 2011 report from PricewaterhouseCoopers modelled the effect of future heatwaves on Melbourne and found that, by 2050, climate change could multiply annual average heat-related deaths by five. Melbourne isn't alone — the 'State of Australian Cities 2013' report predicted heat-related deaths to increase dramatically in Perth and Brisbane.

Unfortunately, the majority of Australian homes are reported to be 20 or more years old, and they don't cope well in long periods of very hot weather. A CSIRO analysis published in 2013 by the National Climate Change Adaptation Research Facility modelled the performance of 10 typical housing types during the January 2009 Melbourne heatwave and found that a safe temperature threshold was breached in every single house type, although insulation did significantly reduce the duration of the risk.

If you lived in a 'worst case' house — with poor orientation, a dark roof and no insulation — you'd probably be better off outdoors.

Newer houses generally have improved insulation, but a 2008 study found the energy-efficiency of residential buildings has been 'outpaced by the rate of increase in average floor area'. Despite having higher energy ratings, our big new homes require more energy to heat and cool overall.

Not surprisingly, more Australians now own air conditioners and evaporative coolers — up from 59 per cent in 2005 to 73 per cent in 2011. This has advantages, as the quick relief of artificial cooling can save lives during a severe heatwave.

But while offering a short-term solution for individuals, air conditioners increase the long-term vulnerability of society. Firstly, their use ramps up peak energy demand, leading to power outages and 'load shedding' to make up for the shortfall in electricity. When electricity consumption topped 10,000 megawatts in Victoria on 15 January this year, tens of thousands of people were left without power.

Secondly, increased peak demand requires additional infrastructure, which jacks up electricity prices for everyone, but is particularly devastating for the poor elderly who are most vulnerable to heatwaves. Older Australians on pensions might be reluctant to turn on their air conditioners — or even their fans — due to prohibitively high bills.

What's more, thermal infrared maps of Adelaide, Melbourne, Sydney and Brisbane show concentrations of low-income households in hotter areas of the city with little vegetation. The people who can least afford the cost of summer air conditioning live in locations where it's most needed.

Several proposals have been put forward to address these issues. New 'smart' air conditioners are fitted with devices to allow power companies to switch off the electricity-hungry compressors for short periods during peak loads, potentially reducing power outages. The Australian Medical Association has previously called for government to subsidise the cost of air conditioners for the elderly.

But even with these changes, relying on air conditioning is a risky strategy. As an energy-intensive technology, air conditioning increases carbon emissions that contribute to climate change, fuelling hotter and more frequent heatwaves. The real solutions lie in strategies that keep us cool without simultaneously heating the planet.

The National Climate Change Adaptation Research Facility has put together a framework that recommends a more holistic approach to the spectre of future heatwaves, including retrofitting roofs with reflective surfaces and ceiling insulation. Air conditioners are still part of the solution, but should be regulated to reduce peak demand. Houses could be fitted with a 'cool retreat' in one room, reducing the need to chill the entire interior.

Other reports have recommended more vegetation around the city and a shift from private cooling to collective cooling by establishing public spaces where all citizens can access cool air for free.

Heatwaves are only going to get worse, and air conditioning isn't the godsend it seems. We need to start retrofitting our cities, suburbs and homes to withstand the sweltering summers to come. Any new houses that perform poorly in the heat — like the one I saw on my walk around the block — are going to be a tremendous burden on the next generation.


 

Greg Foyster headshotGreg Foyster is a freelance journalist who has written for The Age, The Big Issue, Crikey and New Matilda. He is also an alumnus of Centre for Sustainability Leadership and the author of Changing Gears: A Pedal-Powered Detour from the Rat Race.

Topic tags: Greg Foyster, climate change, heatwaves, Black Saturday, bushfires

 

 

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Existing comments

Part of the answer to the increased local heat may lie in your first para., Greg. Urban Heat Islands warming from clusters of heat-radiating houses, not "global warming" caused by increased CO2. And the power outages? Because of the draconian constraints on our coal power stations implemented by so-called environmentalists. Deaths galore, as you weep over here, but... it's your fault! You can't force power stations to close and in the same breath complain that there's a shortage of cheap power (particularly when "green" power has been so demonstrably incompetent at the periods of peak demand.) But look: if as you allege, CO2 is the source of all our evils, I have a solution. Instead of demanding people reduce their need for power, why not avail ourselves of what "clean" power out there in virtually infinite supply? Eg: Nuclear power. Not clumsy statist models that gave us Chernobyl and Fukushima. But free enterprise, terrorist-proof, mini power station modules such as those Hyperion Power is rolling out in the US. With, even better, thorium rather than uranium. Whatever. Ah, but wait. That would mean more pesky humans being alive on this planet for longer. I see the dilemma for your mob.
Name | 07 February 2014


Careful please! It is now clear to us that we turn around the sun but it was for a very long time thought that the sun turned around us. The next ice age night be around the corner!
Theo Verbeek | 08 February 2014


Before we even get to all the other aspects of building energy-efficient housing, tree cover, and house size etc, I think one simple measure would be for governments and council to ban black and brown roofs. Every new housing estate that goes up is dominated by black roofs, apparently favoured by builders and buyers alike. Why?
Janet | 08 February 2014


Thank you Greg Foyster - I trust that architects and town planners have begun to address the situation you name. For those of us of low income and living in 'worst case' rentals we already seek refuge from the extreme heat (and extreme cold) in 'public' spaces - libraries, churches, shopping centres, art galleries, shire council buildings. Shire councils and private industry could be encouraged to open more of their available and unused airconditioned space to the the elderly and the vulnerable. In addition to the heat or cold, the increasing trend to single person dwelling magnifies the problem. Thank you for your wise provocations.
susan | 08 February 2014


The comments about heat islands and constraint on fossil fuel power are nonsense. Nuclear power is neither clean nor free. Properly costed for lifetime costs of insurance and dismantling it is a high priced option. evaporative cooling is a relatively low cost option for areas with dry heat with minimal power requirements. Home design needs looking at
Name | 08 February 2014


We recenly built a house in the Southern Highlands of NSW. It has external timber but brick on the inside. Reverse brick veneer. It took a bit to convince the builder and cost more, but we don't have air condititiong. We are surrounded by project homes with ordinary brick veneer and dark coloured concrete tiles. The project home builders are stuck on a 1950's model and they include air conditioners as a bonus. Project home builders are our greatest climate change deniers.
Harry | 08 February 2014


Excellent article. Good points. A pointer to where to start looking to get a house made heat tolerant would have been useful. E.G. http://www.yourhome.gov.au/you-begin
Charles Balnaves | 08 February 2014


Perhaps we should take a leaf out of Coober Pedy people's solution to keeping cool in 40+ temperatures - create living spaces under ground where it can be 21 degrees no matter how cold or hot the outside temperature. And their underground homes are beautiful.
Corrie | 08 February 2014


Planting desciduous trees is a good start - shade in the summer and sun coming through bare branches in the winter. All that lovely mulch in autumn with the dropping leaves. A fire chief recently said part of the problem is gum trees down a country road help the fires spread and European deciduous trees would be much better. Choosing the right tree, now there is the trick. Pyrus calleryana "Capitol" (pear) - 9 down a narrow driveway, 6 malus ioensis plena (crabapple), a lemon and a lime, magnolia soulangeana, camellia japonicas and in autumn I'm planning 4 Japanese maples all on a suburban quarter acre block. There is a murraya hedge across the back and down the driveway also camellia sasanqua hedges around front boundaries with Japanese buxus hedges too. All very easy to look after and hopefully doing my bit for the environment, plus a lot of pleasure.
Jane | 08 February 2014


More detail. In Adelaide this week a 'freak' windstorm (100+kph) created havoc with trees already heat-stressed after 'unusual' weekS of heat. 700 trees came down and tens of thousands of branches. Some power supplies took 48 hours to re-connect. In some areas of the city whole areas had to have their network rebuilt because of falling limbs. Obvious long-term answer - underground powerlines.
Damien Leonard Coghlan | 08 February 2014


I posted my earlier comment before going to: http://ncronline.org/blogs/ncr-today/comments-ncronline-be-part-solution The NCR writer reports, inter alia: The only way to increase civility in comments is to reduce anonymity.
Rodney Stinson | 08 February 2014


Rather depends on how much more than 20 years old the houses are... Ours in Perth is 101 years old this year and performs (thanks to eg verandahs, top opening sash windows and a learned routine of when to close and open up) remarkably well...
Margaret | 08 February 2014


A very timely read, Greg. From my conversations with new house builders and renovators (I have three colleagues that are renovating at the moment) appeal to cost is the most common objection I hear to doing something sensible about dealing with heating and cooling. It's perceived cost, too. People don't put solar panels on their roof because the perceived capital cost makes them baulk. Even if the ongoing costs will be reduced significantly and the system pays for itself in a short space of time. It's for the same reasons people will buy cheap and comfortably replace more often.
Paul Goodsell | 08 February 2014


If I understood what points Name and Theo were making, I'd be glad to respond, but it's not easy to see them. Suffice it to say that 'urban heat islands' may exacerbate the problem in urban areas, but they clearly can't be held accountable for rising rural and ocean temperatures and melting ice-caps, nor the basic problem in urban areas.
Ginger Meggs | 08 February 2014


Well the Gov't had a half hearted attempt at it and started killing off the workers. Roof and WALL insulation can be done safely and relatively cheaply at the construction stage. Double glazed windows are the standard in cold countries and the design/technology is available. Not that cheap to retrofit and the pay back on the cost of cooling cost saving is several years but the sky is not falling.
Townsville Fred | 08 February 2014


As for the colour of the roof, there are a number of roof spraying companies that will not only change the colour but also coating containing an insulating filler. The professionals will use and airless spray so that they are not spraying the nieghbouring homes and cars as well. Professionals will also put a barricade around the edge of the roof to prevent falls from the roof of more than 2.4 m. It all gets expensive which is why the best time to take action is during construction
townsville Fred | 08 February 2014


Thanks for the article Greg. We do need a wide-ranging discussion on these topics but we should also recognise that in Australia we have many climates and the impact of increasing temperatures is different in different parts of the country. Our architectural and residential building responses should reflect these realties. For example, I live in a town which is surrounded by tropical savannah woodland. In my humble view housing here should not be informed by the thermal behaviour of housing built for temperate and mostly coastal urban environments. Every day here is pretty much a heatwave by temperate standards, but every night is a source of daily heat relief. We need housing that capitalises on this daily cycle by maximising air exchange from shaded surrounds during the day and having a light construction that loses heat rapidly at night.
Darryl | 09 February 2014


I share Harry's sentiments about reverse brick veneer. Only yesterday here in Adelaide, after multiple very hot days I left my hotbox of a house - post war, solid brick and bat insulated, to visit my a family who now live in a reverse brick veneer house. The difference was amazing, as is also in winter. I believe reverse brick veneer is definitely the way of the future - its effects closely simulate living a Coober Pedy like underground existence, yet above ground.
John Whitehead | 09 February 2014


I have often wondered about the wisdom of building high rise apartment blocks. They cannot avoid the blazing heat and the apartments need constant air conditioning during daylight hours.
Ingerid | 10 February 2014


For as long as I've lived through Melbourne summers (25 yrs), I have wondered why we don't have houses with lawn roof gardens (like Parliament House).
Susan from Mont Albert Nth | 10 February 2014


Except that those rural temperatures aren't rising, or rising fast enough, are they, GM? Or else, why are tenured warmists such as Matthew England (and others) scurrying around trying to find deep ocean (& conveniently unverifiable) explanations, resembling Ptolemaic epicycles, for the 17-plus year 95% unmodelled "pause" - the very existence of which he rejected with a smug grin a couple of years back in the safety of a stacked Q&A panel & live audience?
HH | 11 February 2014


When I lived in Australia, and I gave it a fair go for 38 years, it was many Councils' policy to cut down any tree over 4 metres. Fools. Trees are the lungs and cooling system of the planet. To bleat now about hot cities is contemptible!
Zoé | 14 February 2014


You didn't mention one of the oldest ways of surviving the heat., The use of fans, loose clothing and drinking plenty of water is still a very effective and energy economical method.
John | 15 February 2014


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